Read Previous Section 6.6.3.2 Tissue Dryer Section Conventional tissue drying is a combination of contact and impingement drying. Today a combination with through drying is often used. So a tissue drying system consists either of a tissue cylinder wrapped by a hood or of a system with an additional through air dryer section ahead of [...]

Read Previous Section 6.6.3.1.2 Multi Cylinder Drying Section : Web Handling In order to reduce the forces acting on the web at high machine speeds a single-tier dryer section is applied where the paper web is continuously supported by a fabric. In the critical areas where the web has to be released from the drying [...]

Read Previous Section Dryer Sections 6.6.3.1 Multi-cylinder Dryer Section 6.6.3.1.1 Types of Multi-cylinder Dryer Section Multi-cylinder dryer sections consist of double-tier or single-tier groups or a com¬bination of both. In double-tier dryer sections (Fig. 6.54) the paper web runs around a large number of cylinders (up to about 60 in graphic paper machines and up [...]

Read the Beginning of this Article 6.6.2.2 Air Impingement Drying This drying principle is mainly used in tissue production or in coating machines but also for enhancing the drying capacity of drying cylinders in multi-cylinder dryer sections. Hot air is blown through a nozzle plate at high velocity onto the paper. The impinging air transfers [...]

Dryer Section 6.6.1 Overview The purpose of the dryer section is to increase the dry content of the paper web, usually to 90 to 98 %, by evaporation. During drying the fibers develop hydrogen bonds which provide the natural strength of the paper. Drying is a coupled heat 6.6 Dryer Section and mass transfer process [...]